The joist AB used in housing construction is to be made from 8-in. by 1.5-in. Southern-pin...

The joist AB used in housing construction is to be made from 8-in. by 1.5-in. Southern-pine boards. If the design loading on each board is placed as shown, determine the largest room width L that the boards can span. The allowable bending stress for the wood is σallow = 2 ksi and the allowable shear stress is τallow = 180 psi. Assume that the beam is simply supported from the walls at A and B